The use of a heat shrinkable plastic as a flexible packaging material for various food stuffs, including meats, has become commonplace in today's food distribution system. Such plastic materials, however, have been susceptable to puncture by protruding bone sections when used to package meat articles having such protruding bone sections. Thus, these materials have not been as effective as is desirable. The use of cushioning materials such paper, paper laminates, cloth and various types of plastic have proved partially successful in solving the puncture problem.
One particularly successful technique for preventing bone puncture in such plastic containers involves the use of a cloth impregnated with a wax such that, prior to packaging of the meat article, the wax impregnated cloth is selectively placed over the protruding bone sections. Such a process is described in U.S. Pat. No. 2,891,870 to Selby. The purpose of the wax is to facilitate the handling of the cloth during its placement over the bone sections of the meat article prior to packaging. The wax additionally helps to maintain the cloth in the porper position during the actual insertion of the meat article into a plastic bag or other container. While the wax impregnated cloth is quite satisfactory for the function for which it was designed, its use requires the presence of additional packaging personnel on a meat loading and packaging line. Accordingly, due to the increased costs associated with labor, it has become highly desirable from a commercial point of view to modify meat packaging process lines in such a manner that the need for the additional personnel who place the waxed impregnated cloth on the protruding bone sections would be eliminated. For this reason the industry as a whole has, in the past, undertaken the quest of reducing or eliminating the labor costs associated with the placing of impregnated wax cloth over the protruding bone sections.
Many techniques for reducing or eliminating the labor costs have resulted from the industry's quest. In general, the techniques are directed to improving the strength and/or puncture resistance of the bag, pouch or other container which is to package the meat article having protruding bone sections. Additionally, as a result of the increased cost associated with most highly puncture resistant materials, many applications were developed which increased the puncture resistance of the container only in preselected areas. These areas would overlie the protruding bone sections and thus protect the container from puncture without unnecessarily raising the cost of the container through over protection. One such arrangement of this sort is described in U.S. Pat. No. 4,136,205 to Quattlebaum. The container disclosed in that patent incorporates a sheet of material which is more puncture resistant than the material utilized for the bag. The sheet of material is utilized on an interior face of one side of the bag. Another patent which is directed to an improved container in this area is U.S. Pat. No. 4,239,111 to Conant. This patent discloses a flexible pouch with a cross-oriented puncture guard secured to an outer surface thereof. The puncture guard preferably has an area less than that of the bag. The puncture guard preferably includes a plurality of oriented sheets which are laminated in cross-oriented relationship. One disclosed pouch structure comprises a patch formed of a pair of facially juxtaposed, cross-oriented sheets of 2.7 mil thick high density polyethylene.
Other patents which have dealt with this problem are U.S. Pat. Nos. 3,264,165; 3,342,613; 3,494,457; 3,559,800; 3,625,348; 3,669,256; 3,741,253; and 4,267,960.
While all of the above-identified patents do offer some degree of relief from the problems associated with excessive labor costs, some of these configurations, by their very nature, present additional problems which have not yet, heretofore, been overcome. In particular, utilization of a flexible bag having a sheet of more puncture resistant material laminated or adhered to either an interior or exterior face of one side thereof in conventional vacuum chamber processes known to those in the art has resulted in a shifting, movement or misalignment of the sheet of more puncture resistant material away from its original alignment over the protruding bone sections of the meat article. This misalignment of the more puncture resistant sheet occurs as a result of the ballooning the bag undergoes during vacuumizing. The ballooning, which will be discussed in greater detail below, effectively results in the physical displacement of the sheet of more puncture resistant material away from its original position which is in alignment with and in overlieing arrangement to the protruding bone sections. The structure of the prior art containers was such that, upon collapse of the ballooned container, the original alignment of the more puncture resistant material with the protruding bone section was partially or totally destroyed. Therefore, those skilled in the art have been searching for a means to improve the final alignment of the more puncture resistant material with the protruding bone sections without having to increase or incur additional labor costs. The present invention is believed to offer a solution to this problem.